Cryptocurrency exchanges using the controversial trans-fee mining (TFM) revenue model have seen their trading volumes rise by 124% in April of this year, a month that saw cryptocurrency exchanges overall see their volumes increase.

According to CryptoCompare’s April 2019 Exchange Review, cryptocurrency exchanges using the controversial revenue model, which some see as a ‘disguise ICO’ over its nature of rebating transaction fees in the form exchange tokens, have been succeeding as the market recovers.

The report reveals that FCoin, a cryptocurrency exchange that hit a $5 billion daily trading volume after introducing the TFM model in June of last year, saw its trading volume increase by 300% to $37.1 billion throughout the month, making it the largest crypto exchange by trading volume.

FCoin’s was followed other exchanges using the TFM model, including CoinBene and ZBG, which saw their volumes grow 51.5% and 81% to $27 billion and $16 billion respectively.

Cryptocurrency exchanges that don’t use the trans-fee mining model also saw their trading volumes grow. OKEx and ZB were the second and third largest cryptocurrency exchanges by trading volumes, registering $35.1 billion and $32.4 billion after seeing their volumes rise by 12.4% and 18.5% respectively.

Overall, exchanges that charge fees traded a total of $52 billion in April, as their volumes rose by 30%, while TFM exchanges traded a total of $115 billion, as their volumes rose by a total of 124%.

Notably, CryptoCompare’s Exchange Review from December of last year showed that exchanges using the TFM model were gaining market share, presumably thanks to incentives given to traders. At the time, Binance was the leading cryptocurrency exchange.

The trend may be concerning for traders, as data has shown exchanges using the controversial model have poor traffic to volume ratios. This means that to see cryptocurrency prices by 10% on these platforms it would take a relatively small amount of their trading volume, compared to other exchanges.

This lack of stability comes from traders being incentivized to trade large amounts in order to rake in token rewards, and could easily lead to ‘flash crashes’. An analysis of CoinBene’s order books in February of this year showed an order taking up 0.3% of its daily trading volume could lead to a 10% price drop. In comparison, Kraken would need an order of 30% of its daily volume to lead to such a drop.